Process for manufacturing barium sulphide



Nov. S, w52?, 1,648,870

v G RlcHARDSoN `PROCESS FOR MANUFACTURING BARIUM SULPHIDE Filed April s,1925 ad, Q,

| l t l l l l lNvENToR l ATT NET? 4 tielly liminnry treatment.

Patented New, i927.

GORDON RICHARDSON, GF NEW YORK, N. Y., ASSIGND F ONE-FOURTH T0 PHANOB J.

EBEE, CF FOREST HILLS, NEW YORK. i

PBOESS FOR MANUFACTURING BLRIVUM SULPHIDE.

Application led. April 8, 19M. Serial No. 21,556.

In the ordinary manufacture of barium sulphide from burytes, the groundore is mixed with coke, or other suitable reduc# ing reagent, and heatedin an open calciuing furnace or sometimes in o rotating furnace of theBrckner type. Under these circumstances, l have found that While thebarium sulphate is reduced, the furnace gases mixed with the nitrogen ofthe utmoshere react with the barium sulphide to erin compounds such assulphites, cyanides, und sulphocyanides, so that in pructice it is noteasy to secure more than eighty per cent conversion of the barytes intowatersoluble barium sulphide. Moreover, these other compounds such oscyanides or sulphucyzinides l have found to be very troublc-4 some anddiiiicult if not impossible to eliminate; and for -man purposes, such esthe manufacture of lit opone, :ire deleterious, lithopone, of course,being o white paint comprising berium sulphate and zinc sulhioe.,

p En the manufacture of lithopone it is de sirable that the interactingchemicals, viz: zinc sulphate and barium sulphide, should be ofexceptional purity in order that the resultin mixture of barium sulphateand zinc su phide should not have their pure whiteness im aired.

it is true t at the cyanide, Sulphocyenide, or complex sulphocyanides ofzinc such as zinc errocyanide, are more or less colorless, but unlikezinc sulphide, which is very stable, these cy'unogen compounds upon erqposure to the influence oi light, uir'ond moisture, ure opt to alter und`become decomposed, und in my opinion the darkening, or greg/ing, ofmany yurieties of: llthopone pointsyrom exposure is due to the presenceor' these undesirable compounds.

In n process l prevent the formation o these yanogencompounds und thusclimin nate :r subsequent diiiiculties resulting from their presence inthe finished lithopone orV other productor process wherein substanurebarium sulphide is advantageous ly usable Describing new my rocess,-whenthe soit compact variety of arys is used, this muy et once be groundwithout any pre- When, however, the herd crystalline yariet is used, Ilhave found it advisable to rst heat this to a. dull redness, under'which treatment the mineral decrepitates und flies to pieces andperilnits it to he finely ground much more casi y.

To insure :i good conversion to bariuni sulphide, the borytes should berround t0 100 de'frces mesh or liner. It is t en mixed carefu ly in abull-mill with a quantit of charcoal calculated in amount to be a ut twoper cent in excess of that re uilred theoreticolly to reduce themineral. stii poste of the combined barytes and charcoal 1s then madewith molasses or dcxtrin. The mess is then molded into cylindrical form6 or 8 inches, more or less, in diameter and 'from l] to E() inches,more or less, in length. The cylinder is mode hollow in the center inthe direction of its axis, the bore being one inch, more or less, indiameter.

This hollowing of the cylinder serves a double purpose. Thus, in thesubsequent heut-ing olthe cylinder, much time would be lost (if therewere no hollen7 bore) to insure the complete conversion of the mafterial in the center, und in the second place, the opening permits therapid elimination of the gases formed in the `decomposition of themineral.

The cylinders are now carefully dried and should be of such a density orhardness preferably that they will resist any ordinary handling or lightblows, and, 1n fact, should almost@ possess u ringin tone when struckwith o liglitobject. Un er these circumstances, jthe conduction of heatthrough the muss is very much facilitated.

rlhe nforesaid cylindrical briqueites are now heated to redness inexternally heated retorts closed against thence-ess of air to theirinterior, or better still internally heated retorts or chambers such :isin electric furnaces of the resistor type in which the resistanceelements are located in or on the inside wall of the furnace Surroundingthe prepared cylinder. `Euch furnace prefer' Aably receives rathersnugly o single cylinder 'leaving only enough clearance at the sides fora pair of tongs, or a like implement, to be used to insert and removethe briquette from the furnace, the object being to minimice the amountof nir initially contained in the furnace. Duringthe heating operation,the furnace is, of course, kept closed aguinst the access of nir tothecontained briquette. 0n the other hand, means is provided for the escapefrom the chamber, retort or furnace l of the quantity of briquettes andthe size/of the furnaces.

" yield of carbon monoxide formed by the reducing action, of thecharcoal or carbon in the briquette on the barium sulphate thereof vinaccordance with the following equation: BaS04+4C=l3aS+ 4C() Since thequantity of carbon monoxide is considerable, it should preferably beconserved and used `ither for the preliminary heating and drying of thebriquettes or for other desirable purposes. The temperature used in saidelectric furnace may be about 1800 l". and each briquette will be heatedfrom two to two and one-half hours, this varying of course, with thesize of tpe n any event, the temperature andl duration of the heatshould be such as to efiectually complete the above reaction. i

The annexed drawingdiagrammatically illustrates one form of electricfurnace With which my process can be carried out. ln said drawing, 1 isthe cylindrical body of the furnace; 2 its lid adapted to be opened andclosed by the handle-means 3 operatively supported by the bracket 4from. the body of thevfurnace. Of course7 said body and lid are providedwith a suitable refractory lining 5. G-'G are the electric resistorheating elements supported against the' cylindrical interior of thelining of the body.

7 is the cylindrical a hollow core 7a. 8 is a gas-escape pipe leadingfrom the interior of the furnace and controlled by a valve 9 permittinggases to escape from the furnace but not to return thereto. The free endof this pipe may lead to a gas-storage tank or other means for disposingof the gas.

L., By my process it will be seen that the reduction of the barytes tobarium' sulphide takes place in a reducing atmosphere of carbon monoxideand Without access 'thereto of atmospheric air, and l obtain a very highbarium sulphide from the aforesaid reaction which takes place from theheating briquette itself having p accedas n 1 of the briquette, saidbarium sulphide being 'ree from contamination with the aforesaiddeleterious cyanogen, compounds.

' Afterthe heating treatnient in the retort for the required period, thebriquette may be removed and covered with charcoal While it cools tokeep it out of contact with atmospheric air.

Then the briquettes may be y broken up and dissolved in Water to make asolution of the barium sulphide, whereupon said solution is-iltered.'l`o make the lithofpone, said barium' sulphide solution is then addedto a solution of zinc sulphate, Whereupon the following reaction takesplace with the precipitation of barium sulphate and zinc lsulphide insubstantially pure forni ready to make up iuto lithopone or into anyother suitable or desirable product:

BasJfznsofBasodzns.

non-oxidizing and non-nitrogenous atmosphere, thereby converting thebarium sulhate to barium sulphide, ,said rocess readily giving a higherthan 80% yield of barium sulphide. y

2. The process of claim 1 further characterized by the briquettes'beingformed of large size 'with hollow cores for the'rapid penetration of theheat through thev entire body of the several briquettes and'for theready escape from the body of the brquettes of the gas generated by thereaction.

Signed at New York, in the county of New York and State of New York,this third day of April, A. D. 1925. ff

